1. Field of the Invention
The present invention relates to a method and a device for monitoring video signal transmission, and more particularly to a method and a device for monitoring video signal transmission in which composite video signals carry identification codes to monitor whether a transmission of composite video signals is correct.
2. Description of the Related Art
Conventional transmission of video signals includes wire transmission and wireless transmission. Wireless transmission, which has no wire in a video transmission system including camera, receiver and display, is beneficial for constructing the video transmission system. However, error is a major problem in the wireless transmission, such as a home security system transmitting video signals through wireless transmission that the video signals may be received by unexpected receiver.
Such error usually occurs in the conventional transmission of analog composite video signals because of a lack of identification code and communication protocol. In other words, any receiver with the same frequency may receive the signals, and multi-signal source may transmit the signals to the same receiver, too.
Nowadays digital wireless transmission is used to transmit video signals to a predetermined target. However, transmission equipment thereof is too expensive to be used in places such as home security monitoring system or car rearview camera system.
Wire transmission has no such problem; however, wires for transmitting signals will restrict the system placement due to a location limitation. An analog video transmission may transmit wrong or false signals without identification code. It usually happens in a wire security monitoring system and causes a loophole.